Memory is often incorporated into integrated circuitry. The memory may be used, for example, in computer systems for storing data.
Memory may be fabricated as an array of individual memory cells, with each memory cell being configured to retain or store memory in at least two different selectable states. In a binary system, the storage conditions are considered as either a “0” or a “1”.
One type of memory cell comprises two electrically conductive electrodes having a programmable material received between them, and may be suitable for utilization in cross-point array architecture. Cross-point array architecture allows for a three-dimensional multilayer stacking of densely-packed memories (i.e., more storage bits per 4F2 footprint). The memory cells in large cross-point arrays can be any of PCM, CBRAM, ReRAM/RRAM, or STT-RAM/STT-MRAM, etc.
A difficulty in utilizing cross-point memory is that there can be a substantial leakage of current through non-selected cells, and such may adversely lead to disturb, wasted power, and errors during writing and retrieval of stored data from a large memory array. Accordingly, diodes or other select devices are commonly paired with memory cells at each cross-point to assist in control of current through the memory cells, such as to reduce the leakage from any half- and un-selected cells.
Some aspects described below pertain to integrated devices suitable for utilization as select devices.